Axial Load Sensor Prevents Casing Drop in Deviated Wells
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Solution Overview
Problem
The existing methods for running casing into a well bore are prone to accidental dropping of the casing string due to insufficient weight support, particularly in cases of short casing strings or highly deviated wells, leading to potential accidents and operational inefficiencies.
Innovation Solution
The implementation of axial load sensors for the casing gripper and spider, which ensure that the casing lifting mechanism supports a minimum weight before allowing the spider to be released, preventing accidental dropping by using a controller to manage the fluid power release mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the spider release mechanism is made easily releasable to improve operational efficiency, then the ease of operation is improved, but the reliability deteriorates as the casing string may be accidentally dropped when the casing lifting mechanism is not properly supporting the weight
Solution Approach 1:
The system uses load sensors to continuously monitor the weight supported by the casing lifting mechanism and provides feedback to the controller. The controller only permits spider release when the feedback indicates sufficient weight support, preventing accidental drops while maintaining operational efficiency.
Solution Approach 2:
A controller acts as an intermediary between the operator and the spider release mechanism. The controller intermediates the release process by checking load sensor signals and only allowing release when safety conditions are met, thus preventing direct accidental release while maintaining ease of operation.
2Reliability
If load sensors and controller system are added to prevent accidental casing drop, then the reliability is improved, but the device complexity increases due to additional sensors, controllers, and interconnection requirements
Solution Approach 1:
The system uses the existing weight of the casing string itself as the safety mechanism. The load sensors simply detect whether this existing weight is being supported, and the controller automatically manages the release based on these detections, eliminating the need for complex active safety systems.
Solution Approach 2:
The patent replaces complex mechanical safety interlocks and physical preventers with electronic load sensing and control systems. This substitution reduces mechanical complexity while achieving reliable prevention of accidental drops through electronic monitoring and control.
3Reliability
If the fluid power release mechanism is made sufficiently strong to prevent accidental release, then the reliability is improved, but the ease of operation deteriorates as the operator cannot release the mechanism when needed
Solution Approach 1:
The system dynamically adjusts the release conditions based on real-time load sensor feedback. The release mechanism remains locked when conditions are unsafe but becomes easily releasable when the controller detects that sufficient weight support is confirmed, providing both reliability and operational flexibility.
Solution Approach 2:
The controller changes the operational parameters of the release mechanism based on load conditions. When load sensors confirm safe conditions, the controller modifies the release mechanism parameters to allow operator-initiated release, while maintaining strong prevention against accidental release when conditions are unsafe.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively prevents the casing string from falling into the well bore by ensuring that the spider is only released when a sufficient weight is supported, enhancing safety and operational reliability during casing operations.
Implementation Method 1
providing an axial load sensor for the casing gripper. The load sensor determines whether the casing lifting mechanism is supporting a minimum amount of weight
Implementation Method 2
The signal from the load sensor will control a release mechanism for the spider
Data Source
AI summary
A method of running casing into a well utilizes a load sensor to avoid dropping the casing string accidentally. The rig has a spider at the rig floor that suspends a casing string in the well when in a gripping position. A casing lifting mechanism will place a new joint of casing on the casing string suspended in the spider. The new joint of casing is rotated to make up with the casing string. After makeup, the casing lifting mechanism lifts the new joint of casing and the casing string. The operator releases the spider to allow the casing string to be lowered further into the well. Before releasing the spider, a load sensor will send a signal indicating that the casing lifting mechanism is supporting a minimum amount of weight.